Methods of forming doped regions in semiconductor substrates

Abstract

Some embodiments include methods of forming one or more doped regions in a semiconductor substrate. Plasma doping may be used to form a first dopant to a first depth within the substrate. The first dopant may then be impacted with a second dopant to knock the first dopant to a second depth within the substrate. In some embodiments the first dopant is p-type (such as boron) and the second dopant is neutral type (such as germanium). In some embodiments the second dopant is heavier than the first dopant.

We claim: 
     
       1. A method of forming a doped region in a semiconductor substrate comprising:
 forming a boron-containing deposit across an upper surface of the substrate while implanting boron within the substrate; 
 impacting the boron-containing deposit with germanium to knock boron out of the deposit and into the substrate; and 
 cleaning the substrate; the cleaning removing the deposit and all of the germanium to leave a doped region within the substrate; the doped region comprising the boron and none of the germanium. 
 
     
     
       2. The method of  claim 1  wherein the forming of the boron-containing deposit and the implanting of the boron comprises plasma doping with B 2 H 6 . 
     
     
       3. A method of forming a doped region in a semiconductor substrate comprising:
 forming a boron-containing deposit across an upper surface of the substrate while implanting boron within the substrate; 
 ion bombarding a material into the substrate to knock boron out of the deposit and into the substrate; the ion bombarding being conducted under conditions which keep all of the material in the deposit; and 
 cleaning the substrate; the cleaning removing the deposit and all of the material to leave a doped region within the substrate; the doped region comprising boron and none of the material. 
 
     
     
       4. The method of  claim 3  wherein the material comprises a primary element heavier than boron. 
     
     
       5. The method of  claim 4  wherein the primary element is neutral-type. 
     
     
       6. The method of  claim 4  wherein the primary element is germanium. 
     
     
       7. The method of  claim 3  wherein the forming of the boron-containing deposit and the implanting of the boron comprises plasma doping with B 2 H 6 . 
     
     
       8. A method of forming a boron-doped region, comprising:
 plasma doping with B 2 H 6  to provide boron dopant within a silicon-containing material; wherein the plasma doping forms a deposit across an upper surface of the silicon-containing material; 
 ion bombarding germanium, in the absence of a plasma, to knock boron dopant out of the deposit and into the silicon-containing material; 
 using the deposit as a screen to protect underlying silicon-containing material from any penetration by the germanium; the ion bombarding being conducted under conditions which keep all of the germanium in the deposit; and 
 removing the deposit and the germanium to leave a boron-doped region within the silicon-containing material.